5% of users account for 75% of all activity, and 10% of users account for 86%. “A steep curve of a small minority of actively engaged content creators generating most of the activity on a site is common among social networks,” notes Bhargava, “but it is steeper and more pronounced on Twitter.”

21% of Twitter’s registered users have never posted a single tweet. Bhargava speculates these dormant users are simply staking out a user name for later use or just never followed through after signing up.

50.4% of all Twitter users post infrequently (less than once a week).

94% of Twitter accounts have fewer than 100 followers.

The reciprocation limit for followers is around 150. Bhargava wrote, “In a particularly interesting data point from the survey, Sysomos found that Twitter users tended to ‘follow back’ all their followers up until about 150 connections. Then the reciprocation rate fell off dramatically.”

Tuesday tends to be the most popular day for tweets. The next most active days are Wednesday and Friday.

As Twitter users attract more followers, they tend to Tweet more often. Someone with 1,000 followers will tweet six times per day, on average. Someone with more than 1,750 followers will tweet 10 times per day.